The instant invention relates to electrophotocopying machines, and more particularly to a line scanning illuminating device for use in an electrophotocopying machine requiring the subject to be illuminated by a narrow line of light.
Considerable efforts have been expended toward projecting a line of light onto an original document to be copied in an electrophotocopying machine. Concave reflecting surfaces of circular, elliptical, and parabolic contour and combinations thereof have been used with varying results for varying purposes. For micrifying purposes, that is, to intensify and concentrate reflected light from a source to an area at a predetermined location of lesser size than the area of the source, while minimizing the non-reflected stray light, circular and spheroidal reflecting surfaces have proved to be inadequate permitting an excessively high amount of non-utilized, non-reflected stray light to escape. Another approach to the scan line illumination problem has been that of gradient index fibers, which minimizes space requirements in the electrophotocopying machine, but which experience has shown to be an expensive solution.
The instant invention accordingly utilizes a hyperbolic reflector together with a cylindrical lens to provide the advantages of the gradient index fiber optics in that it requires only a small space for implementation in the electrophotocopying machine and is free of particular mechanical constraints which usually result from small space requirements, but is more economical than the gradient index fiber optics. Another advantage of the instant invention is that it employs a reflector whose curvature is less steep than that of conventional reflectors, thereby substantially reducing the cost of incorporating the reflector component into the electrophotocopying machine.